So was Ralph Nader an egocentric Don Quixote who has possibly handed the country to George W Bush or has his candidacy energised the electoral process, forced Democrats to re-examine their consciences and provided a breath of fresh air into the contaminated US political system?

Mr Nader, the Green party presidential candidate, took 2.7m votes across the nation - around 3% per cent of the vote. Most crucially, he took 97,000 votes in Florida.

Within hours of the count, he was being savaged by the Democrats for having given the presidency to Mr Bush and putting at risk the environment, the minimum wage and a woman's right to choose over abortion. Now Nader supporters are fighting back and the airwaves of the land are echoing to the great "Nader Factor" debate. Has he been proved right or wrong? People's hero or self-centred villain?

One theme among Nader supporters has been that Al Gore cost Mr Nader vital votes rather than the other way round. Many who would have voted for Mr Nader in marginal states such as Washington, Oregon and Pennsylvania and, not least, Florida were persuaded at the last minute to vote for Mr Gore. This, says the Nader camp, means the Green party fell well short of its own target of 5% - needed to get federal funding for the race in 2004 - and that Gore's siren song derailed the Green party of its immediate hopes of being an effective third force.

The Nader camp also argues that exit polls showed fewer than half of Mr Nader's votes would have gone to Mr Gore anyway: 40% of those asked said they would not have voted at all if Mr Nader had not stood and 20% would otherwise have voted for Mr Bush.

Coming to Mr Nader's defence in the radical publication, In These Times, Doug Ireland wrote: "The hysterics among those Democratic liberals and party familiars in the blabbering classes who accuse Ralph Nader of creating a constitutional crisis are spouting nonsense. Nader did receive nearly 100,000 votes in the Sunshine State, but as he kept repeating in the campaign, only Al Gore could beat Al Gore. That's what happened in Florida. If Gore loses there, it's because he failed to carry the seniors, who were supposed to be the Democrats' firewall."

Ireland added: "Nader's great achievement was injecting a radical, systemic critique into the national discourse for the first time since such thinking was ostracized by the cold war. Nader won't be going away. And that's healthy for progressive politics."

Nowhere has the debate been fiercer than in The Nation, a barometer of left-liberal American thinking. Contributing editor Marc Cooper had advocated a Nader vote before the election as the alternative was "to continue to abandon hope and stay paralysed". He concluded after the vote: "This result is far from the best scenario for those who hoped that Nader would hand the Greens substantial future leverage. Given the failure to establish a federally funded national Green party, however, future clout will depend mostly on Nader's ability and willingness to take his list of 75,000 campaign contributors and hone it into an identifiable political entity. That could be rendered even more problematic by those who will blame Nader for a Gore defeat."

Fellow Nation commentator Eric Alterman wrote in an article entitled Left in Shambles: "Nader may have polled a pathetic 2 to 3% nationally, but he still affected the race enough to tip some important balances in favour of Bush and the Republicans. For now, we can expect an ugly period of payback in Washington. Funders will tell him to take a hike. Sadly, his life's work will be a victim of the infantile left-wing disorder Nader developed in his quixotic quest to elect a reactionary Republican to the American presidency."

It is this view that Robert Scheer, formerly of the radical 60s Ramparts magazine, also holds. Writing in his regular slot in the Los Angeles Times, Scheer accused Mr Nader of being "elitist in the extreme" to scorn critics in the women's movement and the unions who tried to persuade him to deflect his support towards Mr Gore. "What Nader did was to impulsively betray a lifetime of painstaking, frustrating but most often effective efforts to make a better world."

Mr Nader is now setting up two new projects, one which will act as a watchdog of how politicians vote. The other, the People's Debate Commission, will campaign for presidential debates in the future to allow access to more than just Democrats and Republicans.

The real test of what Nader did or did not achieve will come over the next two years when it will become clearer how many of those who answered his call to redefine American politics stick around and become involved. Nader and his Green party supporters remain, in the words of one party organiser, "unashamed and unabashed".